Vertical fan



FIG. 1 is a front, top and right-side perspective view of a vertical fan showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a right-side view thereof;

FIG. 7 is a left-side view thereof; and,

FIG. 8 is a rear, top and left-side perspective view thereof.

The broken lines shown represent portions of the vertical fan and form no part of the claimed design. 

CLAIM The ornamental design for a vertical fan, as shown and described. 